Partial answers, suggestions

Hi bcompton,

You have an ambitious list of "wants," and I'll offer some comments and suggestions for you to consider.  I hope you find a way to come up with an approach that will let you achieve your goals.

1. You said you want your young grandson to be able to use the train.  Well, I think that N-gauge would be very difficult for a young child to deal with.  HO not much easier.  Getting cars and locos onto the tracks in the smaller gauges could be a hurdle. Coupling and uncoupling.  When I gave my 5 year old grandson some HO trains, he loved them, but was always accidentally breaking the couplers.  Re-railer tracks would help, but you are not going to put them everywhere.

2. You mention 4x8' layout size and you also talk about a large yard, and maybe needing 30 switches.  It is difficult for me to imagine an HO-scale layout that would fit in that space, give you a large yard, and accomodate trackwork that involves 30 switches.  You might want to get some track planning software (SCARM is good and is a free download, and has libraries for all the popular sectional track brands) to get an idea of what you can fit into a given space.  If you want to do some background reading to give you a solid foundation for layout planning, John Armstrong's book "Track Planning for Realistic Operations" would be a great place to start.

3. DCC and JMRI would absolutely be the way to go given what you are trying to achieve.

4. Controlling switch tracks/aka turnouts via DCC adds a little cost to a basic electrical controlled turnout.  But it need not be much.  You seem to be interested in the electronics and software end of things, so you might find Geoff Bunza's Arduino-based controller interesting.  It is a low cost way to control quite a few turnouts via DCC commands. Check out his great posts:  SMA 20 decoder

4. Uncoupling automatically can be done, but it can be finicky.  You would have to locate electromagnetic uncouplers (Kadee makes them) at specific spots under the tracks.  The uncouplers work best if they are pretty close to the rails.  I believe it would be a problem to figure out how to mount them and make them work effectively with sectional track.

These are just some thoughts to partially address you questions.  A top level suggestion: you might want to start small: get some sectional track, a few turnouts, a loco or two, some rolling stock and a DCC control system and just mess around and see what it feels like and what your grandson is capable of doing.  Then, you could add JMRI and start writing your software to have the trains do interesting things automatically.  Build up to your grand vision after a modest start.

For so many of us, this hobby is about the journey and all the different things there are to do.  Enjoy!

Dennis

  "Setting up easy ways for

For kids who love trains I'd recommend a Lionel Thomas the tank train for starters. They run great and are very rugged for play use. Five of my grandkids have played with our Thomas set and it's still going strong. As the kid grows you can switch the equipment to more realistic Lionel or other O gauge equipment. If the kid wants to switch to a small scle at some point  they'll then know what appeals to them and will be better able to handle the smaller stuff. ......DaveB

start small

"Switches: for the large switch yard, I'll need *lots* of switches, like maybe more than 30."

You can't use a 4'x8' for this, maybe 40'x80'.

If you are a true beginner, start small.

Instead of 30+ switches

Dear Bcompton,

30+ switches will eat up a lot of real estate, much more than the allotted 4x8.  Have you considered a transfer table?  The transfer table could be powered by a stepper motor and controlled by an Arduino and stepper driver chip.  This fits nicely into your self-programming concept.

JMRI can run on a Raspberry Pi.  With DCC you will need some kind of command station.  DCC++ uses an Arduino and H-bridge motor controller.  Sprog works well with JMRI and there is the Pi Sprog that combines the RPi with a Sprog.

Servos can be used to power switches and controlled by Arduinos and JMRI or your home-brewed sketch (program).  You will need some type of detection to know where the loco and cars are.

One good place to research for ideas is the series of Small Model Animation projects by Geoff Bunza.  His blogs can be found at  https://forum.mrhmag.com/journals-was-blogs-891775 

Good luck with your project.

You don't need a yard with 26 tracks.

You should have tracks in the yard that can hold at least 5-6 cars each plus a place to be able to make up a train.  On a 4x8 you won't have room for a 26 car train, especially if you use Lionel O27 trains.  You might reduce the number of cars needed by eliminating little used letters.  I think that rather than trying to use trains to make the entire alphabet, I would use some other vehicle for teaching the alphabet, but put letters on the cars and have the kids start making up simple words.  That may mean that you need extra cars for letters that are often repeated in words like vowels as well as consanents like L, N, R, S, & T that are frequently used in doubles. 

You could do it in HO scale, I would use Kato Uni-track, and get Rix railers to put the cars on the track with.  The Rix railers is a wedge of plastic with a raised section in the center that aligns with the track and you just put a car on it and let it roll down.  It is made to fit over a straight section of track and reliably rails any car that you let run down grade.  Also it is cheap.

You might need to put the locomotive on the rails.  I would use a small 4 axle switch engine like a Gp unit or a switch engine.  They are easier to get all of the wheels on the track than steam engines or 6 axle diesels.  Also on a 4x8 you will need to use short radius curves like 18 inch or perhaps even 15 inch radius.  I woulld also recomend that you stick to 40' cars or even 36'.  Roundhouse brand old time cars would work best on short radius, but would not be prototypical for use with a diesel switch engine, but kids probably won't notice the difference anyway.  I don't know if Kato has a rerailing section like the Atlas rerailrer, but if they do putting it on a straight section of the railroad would allow easy railing of the locomotive.  If they don't you might be able to figure out how to adapt an Atlas rerailer track to the Kato Uni-Track system. 

Thomas engines are available in HO scale, but I would not use them unless you have powered frogs in all switches.  I don't know much about Kato Uni-Track switches, but most switches have plastic frogs and the Thomas  engine will stall out on "dead" frogs.

Simplicity

O scale is indeed better than HO scale for small kids.  Actually, you can build a pretty decent railroad in N, HO, or O scale on a sheet of plywood. It's been done thousands of times. This does depend on age and temperament, however.  Young children or children that handle items roughly would do better with O scale.  HO scale is fine if the children are a bit older or they know how to handle fragile items. I really wouldn't try N scale until children are into double digits. The difference between a responsible 10 year old and a rambunctious 8 year old is remarkable.

The hiccup with O scale is that one of the two major companies is closing its doors, MTH.  I'm sure it will eventually be back under new ownership or a different name, but for the moment the only future-proof choice is Lionel.  I was sad when K-Line closed years ago. I still have a bunch of that "shadow" rail that I love.

My only real suggestion of consequence is to keep your set up simple.  Large yards on small layouts make very little sense.  With a 4x8 sized layout, one of the 4ft ends can fit against a wall.  You could then run a shelf perpendicular to the layout  in one direction or the other.  If it's 12 inches deep, that's enough for 6-8 tracks in N scale, 4-5 tracks in HO scale or 2-3 tracks in O scale for staging. No matter what, just don't over do it.  Turnouts are expensive and the best designs use a minimum of track to achieve the operating goals of the railroad.

You'll find that incorporating DCC into everything gets expensive quick, but a small layout can be run with a DCC++ homemade base station connected to a computer.  I wouldn't worry about Raspberry Pi, just use an old computer.  If you like to program stuff then I'm assuming you've got a couple of desktops and monitors laying around. Ironically, the kids pick up the electronics part much faster than the physical aspects of the hobby. It's the opposite for us adults (even a 25yr old like myself can't keep up with the pace of things).

Turnouts can be bought "DCC Ready" but that just means you don't need to modify them. You'll still need switch machines, like Tortises, and decoders that can control the turnouts with DCC. In HO scale, that ends up being about $40-50 per turnout.  Best way to save money is to do what the prototype does.  Eliminate any redundant trackage, minimize the number of turnouts, and only power the ones that are of consequence to mainline operation.  Spur tracks, yards, and other short stretches of track don't need the same automation as the mainline for autonomous running.

Hey folks! Wow – I was

Hey folks!

Wow – I was expecting I could get some helpful advice from experienced people, and this is really awesome!  So many great recommendations here it’ll take me a little while to work through them. A few quick hits –

So much to unpack here. Thanks again!

One other consideration

This will depend completely on the space available, but if this 4x8 layout is supposed to be in the middle of a room, you can fit a lot more onto a railroad the runs around the walls of a room rather than sitting in the middle. For continuous running it just requires a duck under or a lift out section. The 4x8 is a great starting size for a model train layout but it requires an 8x10 room in order to access every inch of the layout.